“That’s a pretty huge number,” said Karen Weller, director of the Office of Community Health and Planning at the Miami-Dade Health Department. “People are living sedentary lifestyles, not walking, kids doing video games instead of going outside to play. Portion sizes have a very big impact. Restaurants want to give big portions. People get insulted if they don’t.”

America’s fattest state is Mississippi, with 34.4 percent obesity. The skinniest is Colorado, with 19.8 percent. But even the mountain state nearly doubled in girth since 1995. The South tends to be fattest, the Northeast and West less so — but still fatter than 15 years ago.

“This is the most challenging health crisis this country has ever faced,” said Jeff Levi, CEO of the trust. “It impacts at least 20 diseases, including diabetes and heart problems.”

The 124-page report, titled “F as in Fat: How Obesity Threatens America’s Future,” is on the trust’s website at healthyamericans.org.

Obesity is no equal-opportunity epidemic, the report says.

“Racial and ethnic minority adults and those with less education or who make less money continue to have the highest overall obesity rates,” the report says.

In Florida, the rate of obesity for African-Americans is 38.8 percent. For Hispanics, it’s 28.7 percent, and for non-Hispanic whites, it’s 24.1 percent.

One-third of Floridians earning less than $15,000 a year are obese, but only a quarter of those who earn more than $50,000.

Individuals with a body mass index (based on the ratio of weight to height) of 30 or higher are considered obese.

In the 15 years between 1995 and 2010, as Florida was getting fatter, diabetes was also on the rise, going from 5.7 percent to 9.9 percent. Hypertension grew, too, from 23.8 percent to 29 percent.

It’s not that states aren’t trying.

Miami-Dade won a $14.7 million grant in 2009 from a national program, Communities Putting Prevention to Work, to fight obesity. Through the county’s Consortium for a Healthier Miami-Dade, set up in 2003, the money is being used to help battle the county’s weight problem, bringing together the School Board, county government, the Health Foundation of South Florida and others. The group is helping to establish new farmers markets in Liberty City, Opa-locka and other areas, encouraging farmers to bring fresh fruits and vegetables directly to school cafeterias. Classes teaching good nutrition are being established in schools and community centers, said Weller, of the county’s health department.

Still, the challenge is a big one. Can America push the plate away and get off the couch to reverse its growth spurt?